Friday, August 21, 2020

Tropical Depressions 13 and 14: August 20, Update A

Busy busy busy busy day today (must be a Thursday... never could get the hang of those!), and I'm giving a talk in 30 minutes at 10pm (time is irrelevant when you work from home), so this one is going to be quick! 

Tropical Depression 13 is still a Tropical Depression, as expected with winds of 35mph, central pressure 1008mb. Yesterday's 'she' is now going to be a 'he' (these things happen)... and he's at 17.3N, 56.4W, heading WNW at 22mph. The track has shifted a little to the south, which would match the location being slightly too far north yesterday... 

But along with that, they have increased the intensity to hurricane in a few days. If that track continues to shift south, he'll interact more with the islands, so he will be weaker than currently forecast, but the track as it currently stands is avoiding almost all land, which means he has a chance to intensify. The key is in the track. 

Intensity-wise, he would be a Tropical Storm already because there is good vorticity (circulation) in the lower and mid-levels of the troposphere, but there is some wind shear at the moment, so he isn't vertically aligned - which means his Tropical Storm structure isn't quite in place. I agree with keeping him as a TD for a bit longer - but the wind shear is definitely subsiding so this won't be much of a factor in inhibiting his growth soon. He's also almost through the first batch of SAL, which means he'll be clear of the main clump of dry and dusty air, so this won't be a factor in inhibiting his growth to a Tropical Storm at least. 

He is going to be moving over warmer waters - they are already warm enough to give him energy to grow slowly. So overall, I expect a slow increase in intensity, and it's really the track that will keep him in check for now. 

We can see that the wind shear is still in place because most of his clouds are to the east and south of the center. If you are on the islands, get ready for some 'refreshing' rain... 


We also have Tropical Depression 14 in the Caribbean - this will be Laura! She's officially at 14.9N, 82.2W, heading WNW at 14mph, and about to clip Nicaragua and Honduras. 

She's over some very warm water at the moment, and I think she should already be TS Laura by now - in fact, I think she's close to hurricane strength already because there is some circulation in the upper troposphere! However, the official winds are only 35mph, central pressure is 1007mb, which makes her a TD. 

I have to run now, but I'll most definitely be back tomorrow... things are going to be a little rocky in the Gulf in the next few days! 

Toodles,

J. 

Twitter: jyovianstorm

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DISCLAIMER:
These remarks are just what I think/see regarding tropical storms - not the opinion of any organization I represent. If you are making an evacuation decision, please heed your local emergency management and the National Hurricane Center's official forecast and local weather service announcements. This is not an official forecast. If I "run away, run away" (Monty Python), I'll let you know. 
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